Housing for an electronic circuit with two separable housing parts

ABSTRACT

A housing for an electronic circuit, in particular for an electronic control circuit of a motor vehicle internal combustion engine has a circuit accommodation area, a connection area, a distribution area, and a connection device for a separable electrical connection of information and supply leads. The housing has two housing parts which are separable from one another and include a first housing part having accommodating area and a second housing part having the connection area for the connection device and having the distribution area. A dividing part separates the connection area and the distribution area. Contact connections for the connection device are provided on the dividing part. The first housing part has a base wall which in a closed condition of the housing closes the second housing part.

BACKGROUND OF THE INVENTION

The invention concerns a housing for an electronic circuit, inparticular for electronic control circuits for motor vehicle internalcombustion engines, with a circuit accommodation area and a connectiondevice for separable electrical connection of information and supplyleads.

To enable correct functioning of an electronic circuit, it is often ofdecisive importance in vehicle engineering to accommodate this within ahousing which is sealed against the environment, so as to prevent anymoisture and the like from penetrating. The connection area forinformation and supply leads represents a particularly weak point withregard to tightness of sealing. Moreover, the reliability of function isdependent on the electromagnetic compatibility (EMC) of the electroniccircuit, i.e. the housing should create a sufficiently high shieldingeffect. At the same time, the invention is aimed at providing a simplestructure and high service- and diagnosis-friendliness.

From the DE-OS 25 54 747, a housing for an electronic control unit isknown, which has panels consisting of an electronic circuit board and alid. The circuit board and the lid are riveted together. The rivetconnections make access to the electronic circuit more difficult.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide ahousing for an electronic circuit, which avoids the disadvantages of theprior art.

In keeping with these objects and with others which will become apparenthereinafter, one feature of the present invention resides, brieflystated, in a housing for an electronic circuit in which two housingparts are separable from each other, wherein a first housing part has acircuit accommodation and a second housing part accommodates aconnection device.

When the housing is designed in accordance with the present invention,it has the advantage that, with a hermetically sealed and safeconfiguration, it is readily amenable to service and diagnosis. Thehousing consists of two parts which can be separated from each other andwhich take on different tasks. The first housing part has a circuitaccommodating area, in which the electronic circuit can be arranged. Thesecond housing part serves to provide the electrical connection forinformation and supply leads entering from the outside. Due to theseparable construction of the two housing parts, good accessibility andhigh amenability to servicing and diagnosis is achieved. Due to thesegregation of the electronics from the connecting device for theinformation and supply leads, there is a high sealing protection, makingsuch a housing suitable even for external mounting on a vehicle. Even ifmoisture and the like should penetrate, through lead entrances, into thesecond housing part and to the connection device, the electronic circuitwill be protected by virtue of the separate first housing part.

In a preferred arrangement, the two housing parts are connected to eachother via a hinge. This provides for high maintenance-friendliness,since hinging open of the two housing parts enables easy access tolocations which otherwise would be difficult to reach.

The connection area is separated from the distribution area preferablyby a dividing wall in which the contact connections are sealed. Thedividing wall thus forms yet another moisture barrier. According to apreferred embodiment example, the connection area can have an outletwith a labyrinth seal which, although it permits ventilation anddischarges moisture which may have entered via the cable entries, doesnot allow any moisture to enter. The separate connection area makes itpossible to arrange in a second housing part, namely in the distributionarea, such components which do not directly form part of the electroniccircuit, but which are also moisture-sensitive, such as relays, fuses,and diagnostic LEDs. An evaluation of the diagnostic LEDs may reveal afault, without the necessity of opening the circuit location area.

The contact connections of the sealed connection device will preferablylead directly to a board which is arranged in the distribution area.This provides not only a simple structure, but also high reliability offunction.

It is envisaged, in particular, that the two housing parts form twohousing levels, one of these levels containing the electronic circuit,and the other level serving the connection and distribution function.

The second housing part has a tray-like shape and can be closed with thebase wall of the first housing part. The base wall thus separates thecircuit locating space both from the connection area and thedistribution area. When the housing is opened, the circuit accommodationarea is still closed, whereas the connection and distribution areas areaccessible.

Seals are provided for hermetically sealing the two housing parts.

In accordance with a preferred embodiment example, the base wall of thefirst housing part has been configured so as to be removable. The hingeallows both housing parts to fold open, with the base wall beingremovable in this opened position. In the opened position, allcomponents are readily accessible. To seal the circuit location, thebase wall is preferably connected to the remaining first housing part,which is also tray-shaped, via seals. The hinge preferably connects thetwo tray-shaped housing parts and does not, therefore, engage on thebase wall.

In accordance with another embodiment example, the base wall also formspart of the hinge. Both the first housing part and the base wall haveextensions which together, in the assembled condition of base wall andhousing part, form a hinge fork, which engages on a hinge pin of thesecond housing part. On operation of the hinge, during which the firsthousing part together with the base wall is offset relative to thesecond housing part, the outside of the extension which is allocated tothe base wall lies opposite a mating bearing surface of the secondhousing part, thus allowing release only after a certain angle ofopening is reached, with the jaw opening of the hinge fork allowingthrough-passage of the hinge pin.

If the hinge valves can be separated from each other in the openposition, then the housing can also be taken apart. This is particularlyimportant for the replacement of entire components, such as the firsthousing part which contains the electronic circuit.

For easy separation and joining of the two housing halves, a sealedelectrical plug-type connection is provided, which leads from thedistribution area and into the circuit location area. This connectionhas a contact element and an opposite contact element, in which thecontact element is connected via a flexible, strain-relieved lead to theboard, which is arranged in the distribution area.

A particularly high reliability of function is obtained when theopposite contact element is arranged in an electrically screenedante-room of the first housing part. The ante-room can also accommodatecomponents which are liable to cause radio interference. The electroniccircuit, which is housed in the circuit locating area, is therefore notsubject to a function reducing interference irradiation.

It is envisaged, in particular, that the information and supply leadsare routed via as sealed, strain-relieved cable entry into theconnection area. In this way, the connection device for the separable,electrical connection of the information and supply leads is alsoprotected against corrosion and the like. The connection of informationand supply leads is preferably made via plug-type connectors.

The housing parts, in particular, are manufactured as metal diecastings.The same is true of the base wall and the dividing walls between theconnection area and the distribution area, and between the ante-room andcircuit locating area. The cable entry is also preferably a diecasting.

The novel features which are considered as characteristic for theinvention are set forth in particular in the appended claims. Theinvention itself, however, both as to its construction and its method ofoperation, together with additional objects and advantages thereof, willbe best understood from the following description of specificembodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 a longitudinal section through a housing for an electroniccircuit,

FIG. 2 a plan view of the housing in FIG. 1, viewed in the direction ofthe arrows x and y, and

FIG. 3 a detail view of a housing hinge.

DESCRIPTION OF AN EMBODIMENT EXAMPLE

The FIG. 1 shows a housing 1 for a preferred electronic circuit 2, whichis designed as the electronic control circuit of a motor vehicleinternal combustion engine. The electronic circuit 2 is arranged on acircuit board 3.

The housing 1 is composed of two housing parts 4 and 5, which can beseparated from each other. The first housing part 4 has a circuitlocation area 6, and the second housing part 5 has a connection area 7and a distribution area 8. Both housing parts 4 and 5 are manufacturedas tray-shaped, metal diecastings. They are linked to each other and aremovable via a hinge 10 which is arranged on the lateral edge 9 of thehousing 1. In the closed condition, the two tray-shaped housing parts 4and 5 with their locating apertures, are opposite each other, with abase wall 11 of the first housing part 4 arranged between them and atthe same time forming an upper wall for the second housing part 5. Thetwo housing parts 4 and 5 thus form two housing levels 12 and 13. Thecircuit locating area 6 is located in the housing level 12, connectionarea 7 and distribution area 8 are arranged in the housing level.

The second housing part 5 thus forms a base part of the housing 1 and isprovided with fixing flanges 14 for its mounting. Both housing parts 4and 5 have flange collars 15 or 16 formed all around the tray edge andhaving threaded holes 17 or through holes 18 for setscrews, not shownhere, with which the two housing parts 4 and 5 can be fixed. On itsflange collar 15, the housing part 5 has an all-round groove 19 for aseal 20 which is clamped by an annular web 21 of the base wall 11.

The flange collar 16 of the housing part 1 is also provided with anall-round groove 22 accommodating a seal 23, which acts in conjunctionwith an annular web 24, arranged on the other side of the base wall 11.

One of the side walls 25 of the connection area 7 is designed as a cableentry 26 for information and supply leads 27. The cable entry 26consists of a base part 28 which forms one piece with the housing part 5and is clamped with a pressure piece 29. Due to the clamping of the basepart 28 and the pressure piece 29, a strain relief is formed for theinformation and supply leads 27. The pressure piece 29 forms a wall areaof the housing part 5. The cable entry 26 is preferably provided with aseal which engages on the casing walls of the information and supplyleads 27, so that moisture is prevented from entering into theconnection area 7.

The cores 30 of the information and supply leads 27 are connected viaplug-type connectors 31 to contact connections 32 of a connection device33. With its connection area 34, this device passes through a cut-out 35of a dividing wall 36 which is formed on the housing part 5 as onepiece, and which partitions the connection area 7 from the distributionarea 8. The connection device has a flange area 37 which is fitted witha seal 38 and lies against that side of the dividing wall 36 which facestowards the distribution area 8. The front face 39 of the dividing wall36 has a groove 40 which terminates in the groove 19 and which carries aseal 41, which acts in conjunction with a web 42 of the base wall 11.

The contact connections 32 of the connection device 33 are directlyconnected to conductor tracks of a circuit board 43 which is arranged inthe distribution area 8 and which accommodates relays 44 and fuse anddiagnostic LEDs and the like, not shown here. Flexible leads 45 areconnected to the board 43, these leads are held by a strain relief 46.The leads 45 run to a contact element 47 of an electrical plug-typeconnection 48. The contact element 47 is plugged together with anopposite contact element 49, which is hermetically sealed in a cut-out51 of the base wall 11 by means of a seal 50.

With its connection area 52, the opposite contact element 49 is in anelectrically screened ante-room 53 of the housing part 4, separated fromthe circuit locating area 6 by a transverse wall 54 which forms onepiece with the housing part 4. The board 3 of the electronic circuit 2penetrates through a slot 55 of the transverse wall 54, so that thecontact lugs of the opposite contact element 49 can be directlyconnected to the conductive tracks of the board 3. The ante-room 53moreover accommodates components, not shown here, which are liable tocause radio interference.

After slackening the setscrews which hold the two housing parts 4 and 5,the housing 1 can be hinged open by the hinge 10, with the opening anglebeing approximately 140°. In this position, the base wall 11 can then beremoved, so that all components are freely accessible. However, it isalso possible to unhook the housing part 4 from the hinge 10 and to undothe plug-type connection 48, so that an exchange or a repair can beeffected in a simple manner.

The housing 1, in particular the circuit accommodating area 6, ishermetically sealed. Even if due to the cable entry 26 being leakymoisture should have entered, this will remain in the connecting area 7which has no sensitive components. The sophisticated sealing systemensures a high degree of protection which permits free frame assembly.Due to the metal diecastings of the housing 1, sufficientelectromagnetic screening is ensured, with components subject to radiointerference--such as suppressor chokes, capacitors, and filters--beinghoused in a special area, namely the ante-room 53. FIG. 3 shows thehousing 1 in the region of the hinge 10 in accordance with anotherembodiment example. Both the first housing part 4 and the base wall 11have extensions 60, 61 which form a hinge fork 63 which has an open jaw.The hinge fork 63 engages on a hinge pin 64 of the second housing part5. In the closed condition of the housing 1 of FIG. 3, the outside 65 ofthe extension 61, which has an arc-like outline, lies opposite a shapematching bearing face 66 of the housing part 5, with very little play.In the position shown in FIG. 3, penetration of the hinge pin 64 throughthe open jaw 62 is thus prevented.

If the housing 1 is opened such that the base wall 11 and the firsthousing part 4 are jointly moved to be offset relative to the secondhousing part 5 (e.g. by 45°), then the open jaw 62, which has a slotwidth `a`, will point downwards, and the outside 65 of the extension 61will be released by the bearing surface 66, so that the hinge pin 64 canpass the hinge fork 63, and the housing 1 can be dismantled. It ispossible, by suitable design, to achieve a separating angle other than45°. The hinge pin 64 is preferably designed as one piece with thesecond housing part 5. This also applies to the extensions 60 and 61 onthe first housing part 4 and on the base wall 11.

It will be understood that each of the elements described above, or twoor more together, may also find a useful application in other types ofconstructions differing from the types described above.

While the invention has been illustrated and described as embodied in ahousing for an electronic circuit, it is not intended to be limited tothe details shown, since various modifications and structural changesmay be made without departing in any way from the spirit of the presentinvention.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can, by applying current knowledge,readily adapt it for various applications without omitting featuresthat, from the standpoint of prior art, fairly constitute essentialcharacteristics of the generic or specific aspects of this invention.

What is claimed as new and desired to be protected by Letters Patent isset forth in the appended claims:
 1. A housing for an electroniccircuit, in particular for an electronic control circuit of a motorvehicle internal combustion engine having a circuit accommodation areaand a connection device for a separable electrical connection ofinformation and supply leads, the housing comprising two housing partswhich are separable from one another and include a first housing parthaving an accommodation area and a second housing part having aconnection area for the connection device and a distribution area, saidfirst housing part having a base wall which in a closed condition of thehousing closes said second housing part; a dividing part which separatessaid connection area from said distribution area and is provided withcontact connections for the connection device; and a board which isarranged in said distribution area, said contact connections beingdirectly connected to said board.
 2. A housing as defined in claim 1;and further comprising a hinge for movably linking said two housingparts with one another.
 3. A housing as defined in claim 2; and furthercomprising a side wall, said housing parts being tray-shaped, said hingeconnecting tray-shaped housing parts in the region of said side wall. 4.A housing as defined in claim 2, wherein said hinge has hinge halveswhich are separable from each other when in an open position.
 5. Ahousing as defined in claim 1, wherein said housing parts form twohousing levels.
 6. A housing as defined in claim 1, wherein said secondhousing part is tray-shaped.
 7. A housing as defined in claim 1; andfurther comprising seals arranged between said housing parts.
 8. Ahousing as defined in claim 1, wherein said base wall of said firsthousing part is removable.
 9. A housing as defined in claim 1; andfurther comprising seals, said base wall being connected with said firsthousing part via seals.
 10. A housing as defined in claim 1; and furthercomprising a sealed electrical plug-type connection leading from saiddistribution area to said circuit accommodation area.
 11. A housing asdefined in claim 1; and further comprising a board, a flexiblestrain-relieved leads, and a plug-type connection which has a contactelement and an opposite contact element, said contact elements beingconnected to said board via said flexible strain-relieved leads.
 12. Ahousing as defined in claim 11, wherein said first housing part has anelectrically shielded ante-room, said opposite contact element beingarranged in said electrically shielded ante-room.
 13. A housing asdefined in claim 1; and further comprising a sealed, strain-relievedcable entry via which the information and supply leads are routed intosaid connection area.
 14. A housing as defined in claim 1, wherein saidhousing parts are metal diecastings.